Re: [Mesa-dev] [PATCH] mesa: implement a display list / glBitmap texture atlas

[Nicolai Hähnle]

On 15.02.2016 11:52, Brian Paul wrote:

This improves the performance of applications which use glXUseXFont()
or wglUseFontBitmaps() and glCallLists() to draw bitmap text.

Basically, we collect all the glBitmap images from the display lists
and put them into a texture atlas.  To render the bitmaps for a
glCallLists() command, we render a set of textured quads where each
quad is textured with one bitmap image.  Actually, the rendering part
has to be done by the Mesa driver or Mesa/gallium state tracker.

Note that GLUT demos that use glutBitmapCharacter() don't benefit
from this.

v2, per Nicolai Hähnle:
- check the max tex rect size is at least 1024.
- add comment in dd.h that texture_rectangle is required.
- in _mesa_DeleteLists(), try to delete the atlas before the list(s)


Thanks!

Reviewed-by: Nicolai Hähnle 


---
  src/mesa/main/dd.h |   9 ++
  src/mesa/main/dlist.c  | 385 +
  src/mesa/main/dlist.h  |  38 +
  src/mesa/main/mtypes.h |   1 +
  src/mesa/main/shared.c |  15 ++
  5 files changed, 448 insertions(+)

diff --git a/src/mesa/main/dd.h b/src/mesa/main/dd.h
index 19ef304..3f5aa5d 100644
--- a/src/mesa/main/dd.h
+++ b/src/mesa/main/dd.h
@@ -35,6 +35,7 @@

  #include "glheader.h"

+struct gl_bitmap_atlas;
  struct gl_buffer_object;
  struct gl_context;
  struct gl_display_list;
@@ -154,6 +155,14 @@ struct dd_function_table {
   GLint x, GLint y, GLsizei width, GLsizei height,
   const struct gl_pixelstore_attrib *unpack,
   const GLubyte *bitmap );
+
+   /**
+* Called by display list code for optimized glCallLists/glBitmap rendering
+* The driver must support texture rectangles of width 1024 or more.
+*/
+   void (*DrawAtlasBitmaps)(struct gl_context *ctx,
+const struct gl_bitmap_atlas *atlas,
+GLuint count, const GLubyte *ids);
 /*@}*/


diff --git a/src/mesa/main/dlist.c b/src/mesa/main/dlist.c
index 0e25efb..afd2d83 100644
--- a/src/mesa/main/dlist.c
+++ b/src/mesa/main/dlist.c
@@ -72,6 +72,9 @@
  #include "vbo/vbo.h"


+#define USE_BITMAP_ATLAS 1
+
+

  /**
   * Other parts of Mesa (such as the VBO module) can plug into the display
@@ -606,6 +609,261 @@ void mesa_print_display_list(GLuint list);


  /**
+ * Does the given display list only contain a single glBitmap call?
+ */
+static bool
+is_bitmap_list(const struct gl_display_list *dlist)
+{
+   const Node *n = dlist->Head;
+   if (n[0].opcode == OPCODE_BITMAP) {
+  n += InstSize[OPCODE_BITMAP];
+  if (n[0].opcode == OPCODE_END_OF_LIST)
+ return true;
+   }
+   return false;
+}
+
+
+/**
+ * Is the given display list an empty list?
+ */
+static bool
+is_empty_list(const struct gl_display_list *dlist)
+{
+   const Node *n = dlist->Head;
+   return n[0].opcode == OPCODE_END_OF_LIST;
+}
+
+
+/**
+ * Delete/free a gl_bitmap_atlas.  Called during context tear-down.
+ */
+void
+_mesa_delete_bitmap_atlas(struct gl_context *ctx, struct gl_bitmap_atlas 
*atlas)
+{
+   if (atlas->texObj) {
+  ctx->Driver.DeleteTexture(ctx, atlas->texObj);
+   }
+   free(atlas->glyphs);
+}
+
+
+/**
+ * Lookup a gl_bitmap_atlas by listBase ID.
+ */
+static struct gl_bitmap_atlas *
+lookup_bitmap_atlas(struct gl_context *ctx, GLuint listBase)
+{
+   struct gl_bitmap_atlas *atlas;
+
+   assert(listBase > 0);
+   atlas = _mesa_HashLookup(ctx->Shared->BitmapAtlas, listBase);
+   return atlas;
+}
+
+
+/**
+ * Create new bitmap atlas and insert into hash table.
+ */
+static struct gl_bitmap_atlas *
+alloc_bitmap_atlas(struct gl_context *ctx, GLuint listBase)
+{
+   struct gl_bitmap_atlas *atlas;
+
+   assert(listBase > 0);
+   assert(_mesa_HashLookup(ctx->Shared->BitmapAtlas, listBase) == NULL);
+
+   atlas = calloc(1, sizeof(*atlas));
+   if (atlas) {
+  _mesa_HashInsert(ctx->Shared->BitmapAtlas, listBase, atlas);
+   }
+
+   return atlas;
+}
+
+
+/**
+ * Try to build a bitmap atlas.  This involves examining a sequence of
+ * display lists which contain glBitmap commands and putting the bitmap
+ * images into a texture map (the atlas).
+ * If we succeed, gl_bitmap_atlas::complete will be set to true.
+ * If we fail, gl_bitmap_atlas::incomplete will be set to true.
+ */
+static void
+build_bitmap_atlas(struct gl_context *ctx, struct gl_bitmap_atlas *atlas,
+   GLuint listBase)
+{
+   unsigned i, row_height = 0, xpos = 0, ypos = 0;
+   GLubyte *map;
+   GLint map_stride;
+
+   assert(atlas);
+   assert(!atlas->complete);
+   assert(atlas->numBitmaps > 0);
+
+   /* We use a rectangle texture (non-normalized coords) for the atlas */
+   assert(ctx->Extensions.NV_texture_rectangle);
+   assert(ctx->Const.MaxTextureRectSize >= 1024);
+
+   atlas->texWidth = 1024;
+   atlas->texHeight = 0;  /* determined below */
+
+   atlas->glyphs = malloc(atlas->numBitmaps * sizeof(atlas->glyphs[0]));
+   if (!atlas->glyphs) {
+  /* give up */
+  

[Mesa-dev] [PATCH] mesa: implement a display list / glBitmap texture atlas

[Brian Paul]

This improves the performance of applications which use glXUseXFont()
or wglUseFontBitmaps() and glCallLists() to draw bitmap text.

Basically, we collect all the glBitmap images from the display lists
and put them into a texture atlas.  To render the bitmaps for a
glCallLists() command, we render a set of textured quads where each
quad is textured with one bitmap image.  Actually, the rendering part
has to be done by the Mesa driver or Mesa/gallium state tracker.

Note that GLUT demos that use glutBitmapCharacter() don't benefit
from this.

v2, per Nicolai Hähnle:
- check the max tex rect size is at least 1024.
- add comment in dd.h that texture_rectangle is required.
- in _mesa_DeleteLists(), try to delete the atlas before the list(s)
---
 src/mesa/main/dd.h |   9 ++
 src/mesa/main/dlist.c  | 385 +
 src/mesa/main/dlist.h  |  38 +
 src/mesa/main/mtypes.h |   1 +
 src/mesa/main/shared.c |  15 ++
 5 files changed, 448 insertions(+)

diff --git a/src/mesa/main/dd.h b/src/mesa/main/dd.h
index 19ef304..3f5aa5d 100644
--- a/src/mesa/main/dd.h
+++ b/src/mesa/main/dd.h
@@ -35,6 +35,7 @@
 
 #include "glheader.h"
 
+struct gl_bitmap_atlas;
 struct gl_buffer_object;
 struct gl_context;
 struct gl_display_list;
@@ -154,6 +155,14 @@ struct dd_function_table {
   GLint x, GLint y, GLsizei width, GLsizei height,
   const struct gl_pixelstore_attrib *unpack,
   const GLubyte *bitmap );
+
+   /**
+* Called by display list code for optimized glCallLists/glBitmap rendering
+* The driver must support texture rectangles of width 1024 or more.
+*/
+   void (*DrawAtlasBitmaps)(struct gl_context *ctx,
+const struct gl_bitmap_atlas *atlas,
+GLuint count, const GLubyte *ids);
/*@}*/
 

diff --git a/src/mesa/main/dlist.c b/src/mesa/main/dlist.c
index 0e25efb..afd2d83 100644
--- a/src/mesa/main/dlist.c
+++ b/src/mesa/main/dlist.c
@@ -72,6 +72,9 @@
 #include "vbo/vbo.h"
 
 
+#define USE_BITMAP_ATLAS 1
+
+
 
 /**
  * Other parts of Mesa (such as the VBO module) can plug into the display
@@ -606,6 +609,261 @@ void mesa_print_display_list(GLuint list);
 
 
 /**
+ * Does the given display list only contain a single glBitmap call?
+ */
+static bool
+is_bitmap_list(const struct gl_display_list *dlist)
+{
+   const Node *n = dlist->Head;
+   if (n[0].opcode == OPCODE_BITMAP) {
+  n += InstSize[OPCODE_BITMAP];
+  if (n[0].opcode == OPCODE_END_OF_LIST)
+ return true;
+   }
+   return false;
+}
+
+
+/**
+ * Is the given display list an empty list?
+ */
+static bool
+is_empty_list(const struct gl_display_list *dlist)
+{
+   const Node *n = dlist->Head;
+   return n[0].opcode == OPCODE_END_OF_LIST;
+}
+
+
+/**
+ * Delete/free a gl_bitmap_atlas.  Called during context tear-down.
+ */
+void
+_mesa_delete_bitmap_atlas(struct gl_context *ctx, struct gl_bitmap_atlas 
*atlas)
+{
+   if (atlas->texObj) {
+  ctx->Driver.DeleteTexture(ctx, atlas->texObj);
+   }
+   free(atlas->glyphs);
+}
+
+
+/**
+ * Lookup a gl_bitmap_atlas by listBase ID.
+ */
+static struct gl_bitmap_atlas *
+lookup_bitmap_atlas(struct gl_context *ctx, GLuint listBase)
+{
+   struct gl_bitmap_atlas *atlas;
+
+   assert(listBase > 0);
+   atlas = _mesa_HashLookup(ctx->Shared->BitmapAtlas, listBase);
+   return atlas;
+}
+
+
+/**
+ * Create new bitmap atlas and insert into hash table.
+ */
+static struct gl_bitmap_atlas *
+alloc_bitmap_atlas(struct gl_context *ctx, GLuint listBase)
+{
+   struct gl_bitmap_atlas *atlas;
+
+   assert(listBase > 0);
+   assert(_mesa_HashLookup(ctx->Shared->BitmapAtlas, listBase) == NULL);
+
+   atlas = calloc(1, sizeof(*atlas));
+   if (atlas) {
+  _mesa_HashInsert(ctx->Shared->BitmapAtlas, listBase, atlas);
+   }
+
+   return atlas;
+}
+
+
+/**
+ * Try to build a bitmap atlas.  This involves examining a sequence of
+ * display lists which contain glBitmap commands and putting the bitmap
+ * images into a texture map (the atlas).
+ * If we succeed, gl_bitmap_atlas::complete will be set to true.
+ * If we fail, gl_bitmap_atlas::incomplete will be set to true.
+ */
+static void
+build_bitmap_atlas(struct gl_context *ctx, struct gl_bitmap_atlas *atlas,
+   GLuint listBase)
+{
+   unsigned i, row_height = 0, xpos = 0, ypos = 0;
+   GLubyte *map;
+   GLint map_stride;
+
+   assert(atlas);
+   assert(!atlas->complete);
+   assert(atlas->numBitmaps > 0);
+
+   /* We use a rectangle texture (non-normalized coords) for the atlas */
+   assert(ctx->Extensions.NV_texture_rectangle);
+   assert(ctx->Const.MaxTextureRectSize >= 1024);
+
+   atlas->texWidth = 1024;
+   atlas->texHeight = 0;  /* determined below */
+
+   atlas->glyphs = malloc(atlas->numBitmaps * sizeof(atlas->glyphs[0]));
+   if (!atlas->glyphs) {
+  /* give up */
+  atlas->incomplete = true;
+  return;
+   }
+
+   /* Loop over the display lists.  They should all contain a